Heretofore, various electronic thermometers have been provided which have employed heat sensing resistive elements in a circuit including a meter which can be adjusted to indicate temperature as determined by the heat applied to the resistive element, such as a resistor or thermistor in a probe adapted to be inserted into a body cavity of humans or animals.
Such previous electronic thermometers have been proven to be economically and technically superior to the customary mercury or glass thermometers for clinical use. However, there has continued to be a need for an electronic thermometer of the variable resistance type which is inexpensive and easy to use in the home, as well as in hospitals or like facilities.
One of the major cost factors in electrical thermometers has always been the use of a meter, either to indicate temperature or to indicate a balanced resistance or null in the usual bridge circuit.
A problem in battery operated thermometers has been that erroneous temperature readings could result from battery drain or age which results in low voltage output.